Best thing I can say is to use a busines card folded lengthwise. Dump the desired weight of the compound into the open capsule, then use a smaller capsule to tamp down slightly. Add in some filler (just something that doesn't matter too much at super low dosage, like Tyrosine or
Taurine), replace the top then weigh again.
Weight the cap again, subtracting the weight of the capsule (around 100mg) and the weight of the active material, and this will give you the required weight of the filler material - which you also need to multiply by 50.
This will give you around a total powder weight. Weigh this out, then it should pretty much fill all 50 caps on the Cap-m-quik at the desired dosage.